Memory and Its Processes• Memory: an active system that receives information

from the senses, organizes and alters that information as it stores it away, and then retrieves the information from storage

• Processes of Memory– encoding: the set of mental operations that people

perform on sensory information to convert that information into a form that is usable in the brain’s storage systems

– storage: holding onto information for some period of time

– retrieval: getting information that is in storage into a form that can be used

Models of Memory• Information-processing model: model of memory

that assumes that the processing of information for memory storage is similar to the way a computer processes memory—in a series of three stages

• Levels-of-processing model: model of memory that assumes that information that is more “deeply processed”—or processed according to its meaning, rather than just the sound or physical characteristics of the word or words—will be remembered more efficiently and for a longer period of time

Figure 6.1 Three-Stage Process of MemoryInformation enters through the sensory system, briefly registering in sensory memory. Selective attention filters the information into short-term memory, where it is held while attention (rehearsal) continues. If the information receives enough rehearsal (maintenance or elaborative), it will enter and be stored in long-term memory.

Models of Memory

• Parallel distributed processing (PDP) model: model of memory in which memory processes are proposed to take place at the same time over a large network of neural connections

Sensory Memory

• Sensory memory: the very first stage of memory; the point at which information enters the nervous system through the sensory systems

• Iconic memory: visual sensory memory, lasting only a fraction of a second– capacity: everything that can be seen at one

time– duration: information that has just entered

iconic memory will be pushed out very quickly by new information, a process called masking

Sensory Memory

• Eidetic imagery: the (rare) ability to access a visual memory for thirty seconds or more

• Echoic memory: the brief memory of something a person has just heard– capacity: limited to what can be heard at any

one moment and smaller than the capacity of iconic memory

– duration: lasts longer that iconic; about two to four seconds

Short-Term Memory

• Short-term memory (STM) (working memory): the memory system in which information is held for brief periods of time while being used– selective attention: the ability to focus on only one

stimulus from among all sensory input• Digit-span test: memory test in which a series of

numbers is read to subjects in the experiment who are then asked to recall the numbers in order– Conclusion: The capacity of STM is about seven

items or pieces of information, plus or minus two items—or from five to nine bits of information.

– “magical number” = 7

Short-Term Memory

• Chunking: bits of information are combined into meaningful units, or chunks, so that more information can be held in STM

• Maintenance rehearsal: practice of saying some information to be remembered over and over in one’s head in order to maintain it in short-term memory (STMs tend to be encoded in auditory form)

• STM lasts from about twelve to thirty seconds without rehearsal.

• STM is susceptible to interference. – E.g., if counting is interrupted, one will have to start

over.

Long-Term Memory

• Long-term memory (LTM): the system of memory into which all the information is placed to be kept more or less permanently

• Elaborative rehearsal: a method of transferring information from STM into LTM by making that information meaningful in some way

Types of LTM

• Procedural (nondeclarative) memory: type of long-term memory including memory for skills, procedures, habits, and conditioned responses; these memories are not conscious, but their existence is implied because they affect conscious behavior

• Declarative memory: type of long-term memory containing information that is conscious and known (memory for facts)

Procedural (Nondeclarative) LTM

• Skills that people know how to do• Also include emotional associations, habits, and

simple conditioned reflexes that may or may not be in conscious awareness

• Anterograde amnesia: loss of memory from the point of injury or trauma forward, or the inability to form new long-term memories. Usually does NOT affect procedural LTM

• Procedural memory (often called implicit memory): memory that is not easily brought into conscious awareness

Declarative LTM• All the things that people know• Semantic memory: type of declarative memory

containing general knowledge, such as knowledge of language and information learned in formal education

• Episodic memory: type of declarative memory containing personal information not readily available to others, such as daily activities and events

• Semantic and episodic memories are forms of explicit memory—memory that is consciously known.

Figure 6.5 Types of Long-Term MemoriesLong-term memory can be divided into declarative memories, which are factual and typically conscious (explicit) memories, and nondeclarative memories, which are skills, habits, and conditioned responses that are typically unconscious (implicit). Declarative memories are further divided into episodic memories (personal experiences) and semantic memories (general knowledge).

Organization of Memory

• LTM is organized in terms of related meanings and concepts.

• Semantic network model: model of memory organization that assumes information is stored in the brain in a connected fashion, with concepts that are related stored physically closer to each other than retrieval cue a stimulus for remembering

Figure 6.6 An Example of a Semantic NetworkIn the semantic network model of memory, concepts that are related in meaning are thought to be stored physically near each other in the brain. In this example, canary and ostrich are stored near the concept node for “bird,” whereas shark and salmon are stored near “fish.” But the fact that a canary is yellow is stored directly with that concept.

Cues to Help Remember• Retrieval cue: a stimulus for remembering• Encoding specificity: the tendency for memory of

information to be improved if related information (such as surroundings or physiological state) available when the memory is first formed is also available when the memory is being retrieved

• Encoding Specificity– state-dependent learning: memories formed

during a particular physiological or psychological state will be easier to recall while in a similar state

Recall

• Recall: type of memory retrieval in which the information to be retrieved must be “pulled” from memory with very few external cues– retrieval failure: recall has failed (at least

temporarily)• Tip of the Tongue Phenomenon

Recall

• Serial position effect: tendency of information at the beginning and end of a body of information to be remembered more accurately than information in the middle of the body of information– primacy effect: tendency to remember information

at the beginning of a body of information better than the information that follows

– recency effect: tendency to remember information at the end of a body of information better than the information ahead of it

Recognition

• Recognition: the ability to match a piece of information or a stimulus to a stored image or fact

• False positive: error of recognition in which people think that they recognize some stimulus that is not actually in memory

Recognition

• Father Bernard Pagano enters a courthouse during his time as a suspect in a series of robberies. He was falsely identified for the crimes committed by another man, who eventually confessed to the robberies. False positives occur when people mistakenly believe they have recognized someone or something that they have actually never seen.

Eyewitness Testimony

• Elizabeth Loftus Study– showed that what people see and hear about

an event after the fact can easily affect the accuracy of their memories of that event

– Eyewitness testimony is not always reliable.

Automatic Encoding and Flashbulb Memories

• Automatic encoding: tendency of certain kinds of information to enter long-term memory with little or no effortful encoding

• Flashbulb memories: type of automatic encoding that occurs because an unexpected event has strong emotional associations for the person remembering it

How LTMs Are Formed• “...Remembering is more like making up a story than

it is like reading one printed in a book.” —John Kihlstrom

• Constructive processing: the retrieval of memories through which those memories are altered, revised, or influenced by newer information

• Hindsight bias: the tendency to falsely believe, through revision of older memories to include newer information, that one could have correctly predicted the outcome of an event

• Monday morning quarterbacking: hindsight bias

Memory Retrieval Problems

• Misinformation effect: the tendency of misleading information presented after an event to alter the memories of the event itself

Reliability of Memory Retrieval

• False memory syndrome: the creation of inaccurate or false memories through the suggestion of others, often while the person is under hypnosis

• Evidence suggests that false memories cannot be created for just any kind of memory. – The memories must at least be plausible.

Forgetting: Ebbinghaus

• Curve of forgetting: a graph showing a distinct pattern in which forgetting is very fast within the first hour after learning a list and then tapers off gradually

• Distributed practice will produce better retrieval than massed practice.

• Encoding failure: failure to process information into memory

Encoding Failure: Which is the correct penny?

It’s me!

Figure 6.10 Which Penny Is Real?Most people do not really look at the face of a penny. Which of these pennies represents an actual penny? The answer can be found on the next slide.

Figure 6.10 (continued) Which Penny Is Real?Most people do not really look at the face of a penny. Which of these pennies represents an actual penny? The answer is A.

Forgetting: Memory Trace Theory

• Memory trace: physical change in the brain that occurs when a memory is formed– decay: loss of memory due to the passage of

time, during which the memory trace is not used– disuse: another name for decay, assuming that

memories that are not used will eventually decay and disappear

• Memories after many years are not explained by memory trace theory.

Forgetting: Interference Theory

• Proactive interference: memory retrieval problem that occurs when older information prevents or interferes with the retrieval of newer information

• Retroactive interference: memory retrieval problem that occurs when newer information prevents or interferes with the retrieval of older information

• Proactive interference: problems driving in England after learning in the U.S.

Figure 6.11 Proactive and Retroactive InterferenceIf a student were to study for a French exam and then a Spanish exam, interference could occur in two directions. When taking the Spanish exam, the French information studied first may proactively interfere with the learning of the new Spanish information. But when taking the French exam, the more recently studied Spanish information may retroactively interfere with the retrieval of the French information.

Formation of LTMs

• Consolidation: the changes that take place in the structure and functioning of neurons when an memory is formed

• Hippocampus: area of brain responsible for the formation of LTMs; see the case of H.M.

Amnesia

• Retrograde amnesia: loss of memory from the point of some injury or trauma backwards, or loss of memory for the past

• Anterograde amnesia: loss of memory from the point of injury or trauma forward, or the inability to form new long-term memories (“senile dementia”); see the case of H.M.

• Infantile amnesia: the inability to retrieve memories from much before age three– autobiographical memory: the memory for events and

facts related to one’s personal life story (usually after age three)

Alzheimer’s Disease

• The primary memory difficulty in Alzheimer’s is anterograde amnesia, although retrograde amnesia can also occur as the disease progresses.

• There are various drugs in use or in development for use in slowing or stopping the progression of Alzheimer’s disease.